In recent years, various patterns can be easily and inexpensively formed on substrates by inkjet printing, and thus inkjet printing is exploited in various fields.
For example, PTLs 1 and 2 respectively disclose a coated steel plate having a metallic substrate, an ink receiving layer containing polyester and an ink layer. When the coated steel plate is manufactured, the ink layer is formed by inkjet printing with a solvent-based ink on the surface of an ink receiving layer formed on the metal substrate. Some of the surface of the ink receiving layer is dissolved in an organic solvent contained in the solvent-based ink to form a rough surface, and thus the solvent-based ink can wet-spread on the ink receiving layer and adhere thereto.
PTLs 3 and 4 respectively disclose a coated steel plate used for a construction plate having a metallic substrate, an ink receiving layer obtained by applying and curing a wrinkle finish paint and an ink layer. When the coated steel plate is manufactured, the ink layer is formed by inkjet printing with a solvent-based or water-based ink on the surface of the ink receiving layer formed on the substrate. The ink can spread through grooves on the surface of the ink receiving layer by capillary action and thus sufficiently wet-spread on the surface.
With regard to inkjet printing, PTL 5 discloses an image forming method using an active ray curable ink, other than a solvent-based ink, that allows stable reproduction of highly defined images on various recording materials. PTL 6 discloses a method for manufacturing a decorative construction plate by inkjet printing using an active ray curable ink on a metallic siding material.
On the other hand, PTL 7 discloses a method for manufacturing a decorative construction plate such as an exterior material, in which, specifically, polar groups are introduced into the surface of a water-based enamel coating film formed on a substrate by frame treatment, thereby improving the wettability of a water-based inkjet ink and the aqueous coating film.